- Synthesis, characterization and crystal structure of a novel tetranuclear oxidovanadium(V) complex derived from N’-(2-hydroxy-3-methoxybenzylidene)isonicotinohydrazide with catalytic property
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A novel tetranuclear oxidovanadium(V) complex, [V4O4(OEt)4L4], where L is the dianionic form of N’-(2-hydroxy-3-methoxybenzylidene)isonicotinohydrazide (H2L), has been prepared and characterized by physico-chemical methods and single crystal X-ray diffraction. The V atom in the complex is coordinated by the phenolate oxygen, imino nitrogen and enolate oxygen of one aroylhydrazone ligand, one pyridine nitrogen of another aroylhydrazone ligand, one deprotonated ethanol oxygen, and one oxo group, forming an octahedral coordination. The oxidation of olefins with the complex as the catalyst was evaluated, which indicated that the complex has effective catalytic efficiency in the oxidation of several aliphatic and aromatic substrates by using tert-butyl hydrogen peroxide as oxidant.
- Qian, Heng-Yu,You, Zhonglu,Zhang, Li
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- A new clade of styrene monooxygenases for (R)-selective epoxidation
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Styrene monooxygenases (SMOs) are excellent enzymes for the production of (S)-enantiopure epoxides, but so far, only one (R)-selective SMO has been identified with a narrow substrate spectrum. Mining the NCBI non-redundant protein sequences returned a new distinct clade of (R)-selective SMOs. Among them,SeStyA fromStreptomyces exfoliatus,AaStyA fromAmycolatopsis albispora, andPbStyA fromPseudonocardiaceaewere carefully characterized and found to convert a spectrum of styrene analogues into the corresponding (R)-epoxides with up to >99% ee. Moreover, site 46 (AaStyA numbering) was identified as a critical residue that affects the enantioselectivity of SMOs. Phenylalanine at site 46 was required for the (R)-selective SMO to endow excellent enantioselectivity. The identification of new (R)-selective SMOs would add a valuable green alternative to the synthetic tool box for the synthesis of enantiopure (R)-epoxides.
- Xiao, Hu,Dong, Shuang,Liu, Yan,Pei, Xiao-Qiong,Lin, Hui,Wu, Zhong-Liu
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p. 2195 - 2201
(2021/04/12)
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- Aerobic epoxidation of styrene over Zr-based metal-organic framework encapsulated transition metal substituted phosphomolybdic acid
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Catalytic epoxidation of styrene with molecular oxygen is regarded as an eco-friendly alternative to producing industrially important chemical of styrene oxide (STO). Recent efforts have been focused on developing highly active and stable heterogeneous catalysts with high STO selectivity for the aerobic epoxidation of styrene. Herein, a series of transition metal monosubstituted heteropolyacid compounds (TM-HPAs), such as Fe, Co, Ni or Cu-monosubstituted HPA, were encapsulated in UiO-66 frameworks (denoted as TM-HPA@UiO-66) by direct solvothermal method, and their catalytic properties were investigated for the aerobic epoxidation of styrene with aldehydes as co-reductants. Among them, Co-HPA@UiO-66 showed relatively high catalytic activity, stability and epoxidation selectivity at very mild conditions (313 K, ambient pressure), that can achieve 82 % selectivity to STO under a styrene conversion of 96 % with air as oxidant and pivalaldehyde (PIA) as co-reductant. In addition, the hybrid composite catalyst can also efficiently catalyze the aerobic epoxidation of a variety of styrene derivatives. The monosubstituted Co atoms in Co-HPA@UiO-66 are the main active sites for the aerobic epoxidation of styrene with O2/PIA, which can efficiently converting styrene to the corresponding epoxide through the activation of the in-situ generated acylperoxy radical intermediate.
- Hu, Dianwen,Song, Xiaojing,Zhang, Hao,Chang, Xinyu,Zhao, Chen,Jia, Mingjun
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- X-ray Structure-Guided Discovery of a Potent, Orally Bioavailable, Dual Human Indoleamine/Tryptophan 2,3-Dioxygenase (hIDO/hTDO) Inhibitor That Shows Activity in a Mouse Model of Parkinson’s Disease
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Human indoleamine 2,3-dioxygenase 1 (hIDO1) and tryptophan 2,3-dioxygenase (hTDO) have been closely linked to the pathogenesis of Parkinson’s disease (PD); nevertheless, development of dual hIDO1 and hTDO inhibitors to evaluate their potential efficacy against PD is still lacking. Here, we report biochemical, biophysical, and computational analyses revealing that 1H-indazole-4-amines inhibit both hIDO1 and hTDO by a mechanism involving direct coordination with the heme ferrous and ferric states. Crystal structure-guided optimization led to23, which manifested IC50values of 0.64 and 0.04 μM to hIDO1 and hTDO, respectively, and had good pharmacokinetic properties and brain penetration in mice.23showed efficacy against the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-induced mouse motor coordination deficits, comparable to Madopar, an anti-PD medicine. Further studies revealed that different from Madopar,23likely has specific anti-PD mechanisms involving lowering IDO1 expression, alleviating dopaminergic neurodegeneration, reducing inflammatory cytokines and quinolinic acid in mouse brain, and increasing kynurenic acid in mouse blood.
- Ning, Xiang-Li,Li, Yu-Zhi,Huo, Cui,Deng, Ji,Gao, Cheng,Zhu, Kai-Rong,Wang, Miao,Wu, Yu-Xiang,Yu, Jun-Lin,Ren, Ya-Li,Luo, Zong-Yuan,Li, Gen,Chen, Yang,Wang, Si-Yao,Peng, Cheng,Yang, Ling-Ling,Wang, Zhou-Yu,Wu, Yong,Qian, Shan,Li, Guo-Bo
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supporting information
p. 8303 - 8332
(2021/06/30)
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- Enantiomer Separation of Nitriles and Epoxides by Crystallization with Chiral Organic Salts: Chirality Switching Modulated by Achiral Acids
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Enantiomer separation of nitriles and epoxides by inclusion crystal formation with organic-salt type chiral hosts was achieved. The stereochemistry of the preferentially included nitrile could be switched only by changing the achiral carboxylic acid component. Crystallographic analysis of the inclusion crystals reveals that the hydrogen-bonding networks are controlled by the acidity of the phenol group of the acids, which results in chirality switching.
- Hirose, Takuji,Kodama, Koichi,Shimomura, Yuki
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p. 6552 - 6557
(2021/11/16)
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- Oxidovanadium(V) and dioxidomolybdenum(VI) Complexes of N'-(3,5-Dichloro-2-hydroxybenzylidene)-4-fluorobenzohydrazide: Synthesis, characterization, crystal structures and catalytic property
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N'-(3,5-Dichloro-2-hydroxybenzylidene)-4-fluorobenzohydrazide (H2L) was used to prepare oxidovanadium(V) complex [VOL(OEt)(MeOH)] (1) and dioxidomolybdenum(VI) complex [MoO2L(OH2)]·[MoO2L(EtOH)] (2). The complexes were characterized by IR, UV-Vis, NMR spectroscopy, and single crystal X-ray diffraction. X-ray analysis indicates that the complexes are mononuclear species with the metal atoms in octahedral coordination. The complexes were studied for catalytic oxidation property on some olefins with tert-butyl hydroperoxide as oxidant.
- Liu, Huan-Yu,Yang, Luo-Ju,Ye, Ya-Fang,Yin, Yi-Shu,Zou, Xiao-Ling
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p. 130 - 136
(2020/03/30)
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- Reprogramming Epoxide Hydrolase to Improve Enantioconvergence in Hydrolysis of Styrene Oxide Scaffolds
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Enantioconvergent hydrolysis by epoxide hydrolase is a promising method for the synthesis of important vicinal diols. However, the poor regioselectivity of the naturally occurring enzymes results in low enantioconvergence in the enzymatic hydrolysis of styrene oxides. Herein, modulated residue No. 263 was redesigned based on structural information and a smart variant library was constructed by site-directed modification using an “optimized amino acid alphabet” to improve the regioselectivity of epoxide hydrolase from Vigna radiata (VrEH2). The regioselectivity coefficient (r) of variant M263Q for the R-isomer of meta-substituted styrene oxides was improved 40–63-fold, and variant M263V also exhibited higher regioselectivity towards the R-isomer of para-substituted styrene oxides compared with the wild type, which resulted in improved enantioconvergence in hydrolysis of styrene oxide scaffolds. Structural insight showed the crucial role of residue No. 263 in modulating the substrate binding conformation by altering the binding surroundings. Furthermore, increased differences in the attacking distance between nucleophilic residue Asp101 and the two carbon atoms of the epoxide ring provided evidence for improved regioselectivity. Several high-value vicinal diols were readily synthesized (>88% yield, 90%–98% ee) by enantioconvergent hydrolysis using the reprogrammed variants. These findings provide a successful strategy for enhancing the enantioconvergence of native epoxide hydrolases through key single-site mutation and more powerful enzyme tools for the enantioconvergent hydrolysis of styrene oxide scaffolds into single (R)-enantiomers of chiral vicinal diols. (Figure presented.).
- Li, Fu-Long,Qiu, Yan-Yan,Zheng, Yu-Cong,Chen, Fei-Fei,Kong, Xu–Dong,Xu, Jian-He,Yu, Hui-Lei
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supporting information
p. 4699 - 4706
(2020/09/21)
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- Synthesis, Characterization and Crystal Structures of Oxidovanadium(V) and Dioxidomolybdenum(VI) Complexes Derived from 2-bromo-N'-(2-hydroxy-3-methoxybenzylidene)benzohydrazide with Catalytic Property
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Abstract: A hydrazone compound 2-bromo-N'-(2-hydroxy-3-methoxybenzylidene)benzohydrazide (H2L) was prepared and characterized by IR, UV-Vis and NMR spectra. Based on the hydrazone compound, a new oxidovanadium(V) and a new dioxidomolybdenum(VI) complexes, [VO(L)(OEt)(EtOH)] (I) and [MoO2(L)(OH2)] (II), were prepared and characterized by IR, UV-Vis, NMR spectra, and single crystal X-ray diffraction (CIF files nos. 1866755 (I) and 1866756 (II)). Complex I crystallizes as the monoclinic space group P21/c with unit cell dimensions a = 12.8733(12), b = 13.5088(13), c = 11.9262(11) ?, β = 91.765(2)°, V = 2073.0(3) ?3, Z = 4, R1 = 0.0524, wR2 = 0.1329, GOOF = 1.245. Complex II crystallizes as the monoclinic space group P21/c with unit cell dimensions a = 8.1140(9), b = 16.2975(19), c = 13.4318(15) ?, β = 106.456(2)°, V = 1703.4(3) ?3, Z = 4, R1 = 0.0296, wR2 = 0.0728, GOOF = 1.046. X-ray analysis indicates that the complexes are mononuclear species with the metal atoms in octahedral coordination. The complexes were studied for catalytic oxidation property on some olefins with tert-butyl hydrogen peroxide as oxidant.
- Liu,Zou,Yang,Ye,Yang
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p. 809 - 816
(2019/11/11)
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- Highly selective and efficient olefin epoxidation with pure inorganic-ligand supported iron catalysts
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Over the past two decades, there have been major developments in the transition iron-catalyzed selective oxidation of alkenes to epoxides; a common structure found in drug, isolated natural products, and fine chemicals. Many of these approaches have enabled highly efficient and selective epoxidation of alkenes via the design of specialized ligands, which facilitates to control the activity and selectivity of the reactions catalyzed by iron atom. Herein, we report the development of the olefin epoxidation with inorganic-ligand supported iron-catalysts using 30% H2O2 as an oxidant, and the mechanism is similar to iron-porphyrin type. With the catalyst 1, (NH4)3[FeMo6O18(OH)6], various aromatic and aliphatic alkenes were successfully transformed into the corresponding epoxides with excellent yields as well as chemo- and stereo-selectivity. This catalytic system possesses the advantages of being able to avoid the use of expensive, toxic, air/moisture sensitive and commercially unavailable organic ligands. The generality of this methodology is simple to operate and exhibits high catalytic activity as well as excellent stability, which gives it the potential to be used on an industrial scale, and maybe opens a way for the catalytic oxidation reaction via inorganic-ligand coordinated iron catalysis.
- Zhou, Zhuohong,Dai, Guoyong,Ru, Shi,Yu, Han,Wei, Yongge
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supporting information
p. 14201 - 14205
(2019/10/02)
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- Unified Mechanism of Oxygen Atom Transfer and Hydrogen Atom Transfer Reactions with a Triflic Acid-Bound Nonheme Manganese(IV)-Oxo Complex via Outer-Sphere Electron Transfer
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Outer-sphere electron transfer from styrene, thioanisole, and toluene derivatives to a triflic acid (HOTf)-bound nonheme Mn(IV)-oxo complex, [(N4Py)MnIV(O)]2+-(HOTf)2 (N4Py = N,N-bis(2-pyridylmethyl)-N-bis(2-pyridyl)methylamine), has been shown to be the rate-determining step of different types of redox reactions such as epoxidation, sulfoxidation, and hydroxylation of styrene, thioanisole, and toluene derivatives, respectively, by [(N4Py)MnIV(O)]2+-(HOTf)2. The rate constants of HOTf-promoted epoxidation of all styrene derivatives with [(N4Py)MnIV(O)]2+ and electron transfer from electron donors to [(N4Py)MnV(O)]2+ exhibit a remarkably unified correlation with the driving force of outer-sphere electron transfer in light of the Marcus theory of electron transfer. The same electron-transfer driving force dependence is observed in the oxygen atom transfer from [(N4Py)MnIV(O)]2+-(HOTf)2 to thioanisole derivatives as well as in the hydrogen atom transfer from toluene derivatives to [(N4Py)MnIV(O)]2+-(HOTf)2. Thus, mechanisms of oxygen atom transfer (epoxidation and sulfoxidation) reactions of styrene and thioanisole derivatives and hydrogen atom transfer (hydroxylation) reactions of toluene derivatives by [(N4Py)MnIV(O)]2+-(HOTf)2 have been unified for the first time as the same reaction pathway via outer-sphere electron transfer, followed by the fast bond-forming step, which exhibits the singly unified electron-transfer driving force dependence of the rate constants as outer-sphere electron-transfer reactions. In the case of the epoxidation of cis-stilbene by [(N4Py)MnIV(O)]2+-(HOTf)2, the isomerization of cis-stilbene radical cation to trans-stilbene radical cation occurs after outer-sphere electron transfer from cis-stilbene to [(N4Py)MnIV(O)]2+-(HOTf)2 to yield trans-stilbene oxide selectively, which is also taken as evidence for the occurrence of electron transfer in the acid-catalyzed epoxidation.
- Lee, Yong-Min,Kim, Surin,Ohkubo, Kei,Kim, Kyung-Ha,Nam, Wonwoo,Fukuzumi, Shunichi
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supporting information
p. 2614 - 2622
(2019/03/04)
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- NOVEL SUBSTITUTED TETRAHYDROQUINOLIN COMPOUNDS AS INDOLEAMINE 2,3-DIOXYGENASE (IDO) INHIBITORS
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Disclosed herein is a compound of formula (I), or a pharmaceutically acceptable salt thereof (I). Also disclosed herein are uses of the compounds disclosed herein in the potential treatment or prevention of an IDO-associated disease or disorder. Also disclosed herein are compositions comprising a compound disclosed herein. Further disclosed herein are uses of the compositions in the potential treatment or prevention of an IDO-associated disease or disorder.
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Page/Page column 88
(2019/05/22)
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- Kinetics of epoxidation by a Musa paradisiaca chloroperoxidase
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Epoxidations of indene, styrene, 2-chlorostyrene, 3-chlorostyrene, 4-chlorostyrene, 4-bromostyrene, and naphthalene using Musa paradisiaca plant juice chloroperoxidase in the presence of H2O2 and t-butyl peroxide as oxidants have bee
- Yadav, Pratibha,Khare, Sunil K.,Sharma, Satyawati
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p. 602 - 609
(2019/05/16)
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- Peroxygenase-Catalysed Epoxidation of Styrene Derivatives in Neat Reaction Media
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Biocatalytic oxyfunctionalisation reactions are traditionally conducted in aqueous media limiting their production yield. Here we report the application of a peroxygenase in neat reaction conditions reaching product concentrations of up to 360 mM.
- Alcalde, Miguel,Arends, Isabel W. C. E.,Hollmann, Frank,Paul, Caroline E.,Rauch, Marine C. R.,Tieves, Florian
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- Asymmetric synthesis of α-bromohydrins by carrot root as biocatalyst and conversion to enantiopure β-hydroxytriazoles and styrene oxides using click chemistry and SN2 ring-closure
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In this study we have combined the bioreduction of α-bromoketones using carrot root as biocatalyst and click chemistry for the preparation of enantiopure β-hydroxytriazoles in excellent enantiomeric excesses and yields. Moreover, we have utilized chiral α-halohydrins for the synthesis of enantiopure styrene oxides in very good yields and enantiomeric excesses. Structural assignments of the products were based on their 1H and 13C NMR data and their optical rotations. The enantiomeric excess of the chiral products was obtained by HPLC analysis.
- Hosseinzadeh, Rahman,Mohadjerani, Maryam,Mesgar, Sakineh
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p. 583 - 591
(2019/02/17)
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- A new enantioselective synthesis of antiobesity drug lorcaserin
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A simple and efficient enantioselective synthesis of anti-obesity drug lorcaerin starting from easily accessible 3-chlorostyrene oxide has been described for the first time employing hydrolytic kinetic resolution as a source of chirality. The protocol might also be useful in the synthesis of structural variants of lorcaserin.
- Ghotekar, Ganesh S.,More, Devidas A.,Nalla, Viswanadh,Muthukrishnan
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p. 16876 - 16880
(2019/11/14)
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- Regio- and chemoselective rearrangement of terminal epoxides into methyl alkyl and aryl ketones
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The development of the highly active pincer-type rhodium catalyst 2 for the nucleophilic Meinwald rearrangement of functionalised terminal epoxides into methyl ketones under mild conditions is presented. An excellent regio- and chemoselectivity is obtained for the first time for aryl oxiranes.
- Tian, Yingying,Jürgens, Eva,Kunz, Doris
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supporting information
p. 11340 - 11343
(2018/10/31)
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- Indazole compounds and application thereof to preparation of IDO inhibitors
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The invention discloses indazole compounds as shown in a formula (i) or (II) which is described in the specification, and a preparation method thereof, and application of the compounds as IDO inhibitors. The compounds provided by the invention can be used for preventing and/or treating a plurality of diseases, such as Alzheimer's disease, cataract, infections related to cellular immune activation,autoimmune diseases, AIDS, cancers, depression, the metabolic disorder of tryptophan or the like.
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Paragraph 0198; 0200; 0201; 0202
(2018/11/04)
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- Arylruthenium(III) Porphyrin-Catalyzed C-H Oxidation and Epoxidation at Room Temperature and [RuV(Por)(O)(Ph)] Intermediate by Spectroscopic Analysis and Density Functional Theory Calculations
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The development of highly active and selective metal catalysts for efficient oxidation of hydrocarbons and identification of the reactive intermediates in the oxidation catalysis are long-standing challenges. In the rapid hydrocarbon oxidation catalyzed by ruthenium(IV) and -(III) porphyrins, the putative Ru(V)-oxo intermediates remain elusive. Herein we report that arylruthenium(III) porphyrins are highly active catalysts for hydrocarbon oxidation. Using catalyst [RuIII(TDCPP)(Ph)(OEt2)] (H2TDCPP = 5,10,15,20-tetrakis(2,6-dichlorophenyl)porphyrin), the oxidation of C-H bonds of various hydrocarbons with oxidant m-CPBA at room temperature gave alcohols/ketones in up to 99% yield within 1 h; use of [nBu4N]IO4 as a mild alternative oxidant avoided formation of lactone from cyclic ketone in C-H oxidation, and the catalytic epoxidation with up to 99% yield and high selectivity (no aldehydes as side product) was accomplished within 5 min. UV-vis, electrospray ionization-mass spectrometry, resonance Raman, electron paramagnetic resonance, and kinetic measurements and density functional theory calculations lend evidence for the formation of Ru(V)-oxo intermediate [RuV(TDCPP)(O)(Ph)].
- Shing, Ka-Pan,Cao, Bei,Liu, Yungen,Lee, Hung Kay,Li, Ming-De,Phillips, David Lee,Chang, Xiao-Yong,Che, Chi-Ming
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supporting information
p. 7032 - 7042
(2018/06/12)
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- Synthesis, Characterization, and Crystal Structures of Dioxomolybdenum(VI) Complexes Derived from Similar Tridentate Hydrazone Compounds with Catalytic Property
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Abstract: Two hydrazone compounds 2-chloro-N'-(2-hydroxy-4-methoxybenzylidene)benzohydrazide (H2L1) and N'-(2-hydroxy-4-methoxybenzylidene)-3-methylbenzohydrazide (H2L2) were prepared and characterized by IR, UV-Vis and 1H NMR spectra. Based on the hydrazone compounds, two new structurally similar dioxomolybdenum(VI) complexes, [MoO2L1(CH3OH)] (I) and [MoO2L2(CH3OH)] (II), were prepared and characterized by IR and UV-Vis spectra, and single crystal X-ray diffraction (CIF files nos. 1566491 (I) and 1566492 (II)). Complex I crystallizes as the triclinic space group (Formula presented.) with unit cell dimensions a = 8.0750(5), b = 10.5223(7), c = 10.8110(7) ?, α = 96.975(2)°, β = 97.909(2)°, γ = 104.497(2)°, V = 869.2(1) ?3, Z = 2, R1 = 0.0323, wR2 = 0.0620, GOOF = 1.089. Complex II crystallizes as the monoclinic space group P21/n with unit cell dimensions a = 11.680(1), b = 10.496(2), c = 14.879(2) ?, β = 98.862(2)°, V?= 1802.2(4) ?3, Z = 4, R1 = 0.0270, wR2 = 0.0675, GOOF = 1.111. X-ray analysis indicates that the complexes are mononuclear dioxomolybdenum(VI) species with the Mo atoms in octahedral coordination. The complexes were studied for their catalytic oxidation property on some olefins with tert-butyl hydrogen peroxide as oxidant.
- Liu,Yang,Diao,Ye,Zou
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p. 572 - 578
(2018/09/11)
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- Dearomative [2,3] sigmatropic rearrangement of ammonium ylides followed by 1,4-elimination to form α-(ortho-vinylphenyl)amino acid esters
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A base-induced dearomative [2,3] sigmatropic rearrangement of amino acid ester-derived ammonium salts followed by 1,4-elimination produced α-(ortho-vinylphenyl)amino acid esters. The reaction of azetidine-2-carboxylic acid-derived ammonium salt, (1S,2S,1′R)-3b, proceeded with a perfect N-to-C chirality transfer to afford α-(ortho-vinylphenyl)azetidine-2-carboxylic acid ester, (R)-5 (99% ee). On the other hand, the reaction of glycine-derived ammonium salt (R)-6a, which involves an efficient chirality transfer from a chiral benzylic carbon to an α-carbon of an ester carbonyl giving the optically active α-(ortho-vinylphenyl)glycine ester, (R)-8a (85% ee), was demonstrated. Although this dearomative [2,3] rearrangement followed by 1,4-elimination has limitations with regard to the structures of the substrates, our method provides unique access to substituted α-arylamino acid derivatives.
- Tayama, Eiji,Sotome, Sho
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supporting information
p. 4833 - 4839
(2018/07/15)
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- Synthesis of cyclic organic carbonates via catalytic oxidative carboxylation of olefins in flow reactors
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Methodology for direct catalytic conversion of olefins into cyclic carbonates using peroxide and carbon dioxide under relatively mild conditions is demonstrated. The protocol utilizes packed bed flow reactors in series to couple rhenium catalyzed olefin epoxidation and aluminum catalyzed epoxide carboxylation in a single sequence.
- Sathe, Ajay A.,Nambiar, Anirudh M. K.,Rioux, Robert M.
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- Potassium phosphate-catalyzed one-pot synthesis of 3-aryl-2-oxazolidinones from epoxides, amines, and atmospheric carbon dioxide
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Potassium phosphate was found to be a highly active catalyst in the three-component cycloaddition of amines, epoxides, and carbon dioxide in DMF at ambient temperature to form 3-aryl-2-oxazolidinones. Atmospheric CO2 and a broad range of amines were employed in this transformation. Aryl isocyanate and 1,2-aminoalcohol were generated in situ as key intermediates. This one-pot reaction is applicable to a variety of terminal epoxides and amines. The key advantages are high yields, simple work-up, inexpensive catalysts, and a practical ten gram-scale synthesis.
- Seo, Ue Ryung,Chung, Young Keun
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supporting information
p. 803 - 808
(2017/08/15)
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- Synthesis, crystal structures, and catalytic properties of two oxidovanadium(V) complexes with tridentate Schiff bases
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Two new oxidovanadium(V) complexes, [VO2L1] (I) and [VO2L2] (II), where L1 and L2 are the deprotonated forms of 4-methyl-2-[(2-morpholin-4-ylethylimino)methyl]phenol (HL1) and 2-[(2-isopropylaminoethylimino) methyl]-4-trifluoromethoxyphenol (HL2), respectively, have been prepared and characterized by physico chemical methods and single crystal X-ray diffraction (CIF files CCDC nos. 1443671 (I), 1443672 (II)). The V atom in each complex is coordinated by the phenolate oxygen, imino nitrogen and amino nitrogen of the Schiff base ligand, and two oxo groups, forming trigonal-bipyramidal geometry. The oxidation of olefins with the complexes as catalyst was evaluated, which indicated that both complexes showed effective catalytic efficiency in oxidation of several aliphatic and aromatic substrates by using tert-butyl hydrogen peroxide as oxidant.
- Peng
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p. 404 - 410
(2017/06/19)
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- Multistep Organic Transformations over Base-Rhodium/Diamine-Bifunctionalized Mesostructured Silica Nanoparticles
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The assembly of multiple catalytic functionalities within a single mesoporous silica as a catalyst for multistep enantioselective organic transformations in an environmentally friendly medium is a significant challenge in heterogeneous asymmetric catalysis. Herein, we took advantage of a BF4 ? anion hydrogen bonding strategy to anchor a chiral cationic rhodium/diamine complex within base-functionalized mesostructured silica nanoparticles conveniently to construct a bifunctional heterogeneous catalyst. The solid-state 13C NMR spectrum discloses the well-defined chiral Rh/diamine active species, and we used XRD, N2 adsorption–desorption, and electron microscopy to reveal the ordered mesostructure. The combination of bifunctionality in the silica nanoparticles enables two kinds of efficient enantioselective organic transformations with high yields and enantioselectivities, in which the asymmetric transfer hydrogenation of α-haloketones followed by epoxidation provides various chiral aryloxiranes, and the amination of α-haloketones with anilines followed by asymmetric transfer hydrogenation produces various β-amino alcohols. Furthermore, the catalyst can be recovered and recycled for seven times without a loss of catalytic activity, which is an attractive feature for multistep organic transformations in a sustainable benign process.
- Liao, Hang,Chou, Yajie,Wang, Yu,Zhang, Han,Cheng, Tanyu,Liu, Guohua
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p. 3197 - 3202
(2017/08/29)
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- Photocatalytic Asymmetric Epoxidation of Terminal Olefins Using Water as an Oxygen Source in the Presence of a Mononuclear Non-Heme Chiral Manganese Complex
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Photocatalytic enantioselective epoxidation of terminal olefins using a mononuclear non-heme chiral manganese catalyst, [(R,R-BQCN)MnII]2+, and water as an oxygen source yields epoxides with relatively high enantioselectivities (e.g., up to 60% enantiomeric excess). A synthetic mononuclear non-heme chiral Mn(IV)-oxo complex, [(R,R-BQCN)MnIV(O)]2+, affords similar enantioselectivities in the epoxidation of terminal olefins under stoichiometric reaction conditions. Mechanistic details of each individual step of the photoinduced catalysis, including formation of the Mn(IV)-oxo intermediate, are discussed on the basis of combined results of laser flash photolysis and other spectroscopic methods.
- Shen, Duyi,Saracini, Claudio,Lee, Yong-Min,Sun, Wei,Fukuzumi, Shunichi,Nam, Wonwoo
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supporting information
p. 15857 - 15860
(2016/12/23)
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- Substrate ionization energy influences the epoxidation of m-substituted styrenes catalyzed by chloroperoxidase from Caldariomyces fumago
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Chloroperoxidase from the fungus Caldariomyces fumago is a versatile heme-peroxidase, which is able to catalyze olefin epoxidation. In this report, the epoxidation of m-substituted styrene catalyzed by chloroperoxidase was studied. The catalytic data fit
- Mu?oz-Guerrero, Fabio A.,águila, Sergio,Vazquez-Duhalt, Rafael,Campos, Cristian H.,Torres, Cecilia C.,Alderete, Joel B.
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- Mononuclear Nonheme High-Spin Iron(III)-Acylperoxo Complexes in Olefin Epoxidation and Alkane Hydroxylation Reactions
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Mononuclear nonheme high-spin iron(III)-acylperoxo complexes bearing an N-methylated cyclam ligand were synthesized, spectroscopically characterized, and investigated in olefin epoxidation and alkane hydroxylation reactions. In the epoxidation of olefins, epoxides were yielded as the major products with high stereo-, chemo-, and enantioselectivities; cis- and trans-stilbenes were oxidized to cis- and trans-stilbene oxides, respectively. In the epoxidation of cyclohexene, cyclohexene oxide was formed as the major product with a kinetic isotope effect (KIE) value of 1.0, indicating that nonheme iron(III)-acylperoxo complexes prefer C? - ?C epoxidation to allylic C-H bond activation. Olefin epoxidation by chiral iron(III)-acylperoxo complexes afforded epoxides with high enantioselectivity, suggesting that iron(III)-acylperoxo species, not high-valent iron-oxo species, are the epoxidizing agent. In alkane hydroxylation reactions, iron(III)-acylperoxo complexes hydroxylated C-H bonds as strong as those in cyclohexane at -40 °C, wherein (a) alcohols were yielded as the major products with high regio- and stereoselectivities, (b) activation of C-H bonds by the iron(III)-acylperoxo species was the rate-determining step with a large KIE value and good correlation between reaction rates and bond dissociation energies of alkanes, and (c) the oxygen atom in the alcohol product was from the iron(III)-acylperoxo species, not from molecular oxygen. In isotopically labeled water (H218O) experiments, incorporation of 18O from H218O into oxygenated products was not observed in the epoxidation and hydroxylation reactions. On the basis of mechanistic studies, we conclude that mononuclear nonheme high-spin iron(III)-acylperoxo complexes are strong oxidants capable of oxygenating hydrocarbons prior to their conversion into iron-oxo species via O-O bond cleavage.
- Wang, Bin,Lee, Yong-Min,Clémancey, Martin,Seo, Mi Sook,Sarangi, Ritimukta,Latour, Jean-Marc,Nam, Wonwoo
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supporting information
p. 2426 - 2436
(2016/03/05)
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- Mononuclear Nonheme High-Spin (S=2) versus Intermediate-Spin (S=1) Iron(IV)–Oxo Complexes in Oxidation Reactions
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Mononuclear nonheme high-spin (S=2) iron(IV)–oxo species have been identified as the key intermediates responsible for the C?H bond activation of organic substrates in nonheme iron enzymatic reactions. Herein we report that the C?H bond activation of hydrocarbons by a synthetic mononuclear nonheme high-spin (S=2) iron(IV)–oxo complex occurs through an oxygen non-rebound mechanism, as previously demonstrated in the C?H bond activation by nonheme intermediate (S=1) iron(IV)–oxo complexes. We also report that C?H bond activation is preferred over C=C epoxidation in the oxidation of cyclohexene by the nonheme high-spin (HS) and intermediate-spin (IS) iron(IV)–oxo complexes, whereas the C=C double bond epoxidation becomes a preferred pathway in the oxidation of deuterated cyclohexene by the nonheme HS and IS iron(IV)–oxo complexes. In the epoxidation of styrene derivatives, the HS and IS iron(IV) oxo complexes are found to have similar electrophilic characters.
- Bae, Seong Hee,Seo, Mi Sook,Lee, Yong-Min,Cho, Kyung-Bin,Kim, Won-Suk,Nam, Wonwoo
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supporting information
p. 8027 - 8031
(2016/09/13)
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- Mononuclear Nonheme Iron(III)-Iodosylarene and High-Valent Iron-Oxo Complexes in Olefin Epoxidation Reactions
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High-spin iron(III)-iodosylarene complexes are highly reactive in the epoxidation of olefins, in which epoxides are formed as the major products with high stereospecificity and enantioselectivity. The reactivity of the iron(III)-iodosylarene intermediates is much greater than that of the corresponding iron(IV)-oxo complex in these reactions. The iron(III)-iodosylarene species - not high-valent iron(IV)-oxo and iron(V)-oxo species - are also shown to be the active oxidants in catalytic olefin epoxidation reactions. The present results are discussed in light of the long-standing controversy on the one oxidant versus multiple oxidants hypothesis in oxidation reactions. On active duty: High-spin iron(III)-iodosylarene complexes epoxidize olefins with high stereospecificity and enantioselectivity. The iron(III)-iodosylarene species, not high-valent iron(IV)- and iron(V)-oxo species, are the active oxidants in catalytic olefin epoxidation reactions. The present results resolve the long-standing controversy on the one oxidant versus multiple oxidants hypothesis in oxidation reactions.
- Wang, Bin,Lee, Yong-Min,Seo, Mi Sook,Nam, Wonwoo
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supporting information
p. 11740 - 11744
(2015/10/05)
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- PPAR-sparing thiazolidinedione salts for the treatment of metabolic diseases
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The present invention relates to novel salts of thiazolidinediones and other pharmaceutical agents that are useful for treating and/or preventing metabolic diseases (e.g., diabetes, or neurodegenerative diseases (e.g., Alzheimer's Disease).
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Page/Page column 111
(2015/09/28)
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- Synthesis, structure, and catalytic oxidation of a molybdenum(VI) complex [MoO2(CH3OH)L]
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A new molybdenum(VI) complex, [MoO2(CH3OH)(L)] (L = N′-(4-diethylamino-2-hydroxybenzylidene)-4-hydroxybenzohydrazide), was prepared and characterized by spectroscopy methods and single crystal X-ray diffraction (CIF file CCDC no. 1038153). The crystal of the complex, C19H23MoN3O6, crystallizes in the triclinic space group P1 with unit cell dimensions a = 6.9824(9), b = 10.206(1), c = 15.302(2) ?, α = 94.399(2)°, β = 101.877(2)°, γ = 104.062(2)°, V = 1025.9(2) ?3, Z = 2, R1 = 0.0317, wR2 = 0.0796, S = 1.060. The Mo atom in the complex is in an octahedral coordination with phenolate O, imino N, enolate O atoms of the ligand L, and one oxo O in the equatorial plane, and with one methanol O and the other oxo O in the axial sites. Crystals of the complex are stabilized by hydrogen bonds. The complex was studied for its catalytic oxidation property on some olefins, with tert-butyl hydrogen peroxide as oxidant.
- Liu,Zang,Lv
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p. 451 - 455
(2015/07/01)
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- Asymmetric epoxidation of alkenes and benzylic hydroxylation with P450tol monooxygenase from Rhodococcus coprophilus TC-2
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P450tol monooxygenase was discovered as a unique and highly enantioselective enzyme for asymmetric epoxidation of some terminal alkenes containing electron-withdrawing groups and benzylic hydroxylation of several ethylbenzenes giving the corresponding useful and valuable products, such as (R)-2- and 3-substituted styrene oxides, (S)-4-substituted styrene oxides, and (S)-benzylic alcohols, in high ee.
- Li, Aitao,Wu, Shuke,Adams, Joseph P.,Snajdrova, Radka,Li, Zhi
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supporting information
p. 8771 - 8774
(2014/07/22)
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- PPAR-SPARING THIAZOLIDINEDIONES AND COMBINATIONS FOR THE TREATMENT OF NEURODEGENERATIVE DISEASES
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The present invention relates to PPARy- sparing compounds and pharmaceutical compositions formulated with such compounds that are useful for treating, delaying the onset of, or reducing the symptoms of a neurodegenerative disorder including Huntington's disease, epilepsy, AMS, and MS.
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Paragraph 0413; 0414
(2014/07/07)
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- Vanadium(V) complexes with hydrazone and benzohydroxamate ligands: Synthesis, structures and catalytic epoxidation
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Two structurally similar vanadium(V) complexes, [VOL1L] (1) and [VOL2L] (2), where L1 is the dianionic form of N'-(3,5-dibromo-2-hydroxybenzylidene)-4-methoxybenzohydrazide, L2 is the dianionic form of N'-(3,5-dibromo-2-hydroxybenzylidene)nicotinohydrazide, and L is benzohydroxamate, were prepared and characterized by elemental analysis, infrared spectra, and single crystal X-ray diffraction. 1 crystallizes in the monoclinic space group P21/c, with unit cell dimensions a = 12.0262(7), b = 16.5629(9), c = 12.3449(8) A, β = 105.160(2)°, V = 2373.4(2) A3, Z = 4, R1 = 0.0376, wR2 = 0.0844, GOOF = 1.058; 2 crystallizes in the monoclinic space group P2 1/c, with unit cell dimensions a = 10.6439(7), b = 16.1968(9), c = 13.1108(8) A, β = 104.180(2)°, V = 2191.4(2) A3, Z = 4, R1 = 0.0521, wR2 = 0.1142, GOOF = 1.018. X-ray analysis indicates that vanadium in the complexes are coordinated by phenolate oxygen, imino nitrogen, and enolate oxygen of the hydrazone, two oxygens of the benzohydroxamate, and one oxo, generating octahedral coordination. Oxidations of olefins with the complexes as catalysts were evaluated. The complexes showed effective catalytic efficiency in oxidation of several aliphatic and aromatic substrates under mild conditions, using tert-butyl hydrogen peroxide as oxidant. 2014
- Li, An-Mei
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p. 2076 - 2085
(2014/08/18)
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- Synthesis and structures of two molybdenum(VI) complexes derived from similar benzohydrazone ligands with catalytic properties
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Two new structurally similar molybdenum(VI) complexes, [MoO 2L1(CH3OH)] (1) and [MoO2L 2(CH3OH)] (2), where L1 is the dianionic form of N′-(2-hydroxy-5-nitrobenzylidene)-2-methylbenzohydrazide and L 2 is the dianionic form of N′-(2-hydroxy-4-methoxybenzylidene)- 2-methylbenzohydrazide, were prepared and structurally characterized by elemental analysis, infrared spectra, and single-crystal X-ray diffraction. 1 crystallizes in the monoclinic space group P21/c, with unit cell dimensions a = 7.941(1), b = 14.337(2), c = 15.141(2) A, β = 92.782(2)°, V = 1721.8(4) A3, Z = 4, R1 = 0.0286, wR2 = 0.0650, GOOF = 1.028. 2 crystallizes in the triclinic space group P-1, with unit cell dimensions a = 8.003(1), b = 10.608(1), c = 10.880(1) A, α = 95.745(2)°, β = 97.627(2)°, γ = 105.762(2)°, V = 872.0(2) A3, Z = 2, R1 = 0.0226, wR2 = 0.0595, GOOF = 1.116. X-ray analysis indicates that Mo in the complexes are coordinated by the phenolate oxygen, imino nitrogen, and enolate oxygen of the benzohydrazone, methanol, and two oxo groups, generating octahedral coordination. The oxidation of olefins with the complexes as catalysts was evaluated, indicating that the complexes showed excellent catalytic efficiency in oxidation of most aliphatic and aromatic substrates under mild conditions using tert-butyl hydrogen peroxide as oxidant. 2014
- Li, An-Mei
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p. 1022 - 1031
(2014/05/20)
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- N′-(3-Bromo-2-hydroxybenzylidene)isonicotinohydrazide and its oxovanadium(V) complex: Synthesis, structures, and catalytic properties
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A new hydrazone N′-(3-bromo-2-hydroxybenzylidene)isonicotinohydrazide (H2L) and its oxovanadium(V) complex, [VOLL′]·2H2O (L′ = 2-hydroxybenzohydroxamate), were prepared and structurally characterized by physico-chemical, spectroscopic methods, and single-crystal X-ray determination. The hydrazone coordinates to V through the phenolate oxygen, imino nitrogen, and enolate oxygen. The hydroxamate coordinates to V through the carbonyl oxygen and deprotonated hydroxyl oxygen. Vanadium in the complex is octahedral. The oxidation of olefins with the complex as catalyst was evaluated, which indicated that the complex showed catalytic efficiency in oxidation of several aliphatic and aromatic substrates under mild conditions, using tert-butyl hydrogen peroxide as oxidant.
- Xiong, Yan,Li, Wen-Hui
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p. 3279 - 3287
(2015/10/20)
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- Syntheses, crystal structures, and catalysis by polymeric dioxomolybdenum(VI) complexes with similar (iso)nicotinohydrazones
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Polymeric dioxomolybdenum(VI) complexes, [MoO2L]n(L= L1= N'-(2-hydroxybenzylidene) nicotinohydrazide for 1, L=L 2= N'-(2-hydroxy-5-methoxybenzylidene)isonicotinohydrazide for 2), were prepared and characterized by physico-chemical, spectroscopic methods, and single-crystal X-ray determination. Complex 1 crystallizes in the orthorhombic space group P212121with a=7.6568(4), b =11.6315(7), c = 15.2211(9)A, V= 1355.59(13) A3, Z = 4, R1= 0.0181, wR2= 0.0464, and S = 1.097. Complex 2 crystallizes in the monoclinic space group P21/n with a=11.2516(6), b=11.8134(7), c= 12.4371(6) A, β = 116.2210(10)°, V=1483.02(14) A3, Z= 4, R1= 0.0399, wR2= 0.0874, and S=1.096. X-ray analysis indicates that Mo in each complex is octahedral with two oxo groups and N2O2donor set of the nicotinohydrazone or isonicotinohydrazone. The complexes are efficient catalysts for oxidation of olefins.
- Xu, Wei-Xiu,Yuan, Yong-Mei,Li, Wen-Hui
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p. 2726 - 2735
(2014/02/14)
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- Novel Ethanediamone Hepcidine Antagonists
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The present invention relates to novel hepcidin antagonists of formula (I), pharmaceutical compositions comprising them and the use thereof as medicaments, in particular for treatment of disorders in iron metabolism, such as, in particular, iron deficiency diseases and anaemias, in particular anaemias in connection with chronic inflammatory diseases (ACD: anaemia of chronic disease and AI: anaemia of inflammation).
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- Economical oxygenation of olefins and sulfides catalyzed by new molybdenum(VI) tridentate schiff base complexes: Synthesis and crystal structure
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New cis-dioxomolybdenum(VI) complexes (MoO2YxCH 3OH) were synthesized using MoO2(acac)2 and 2[(1-hydroxy-2-methylpropane-2-ylimino)methyl]phenol derivatives as tridentate ONO donor Schiff base ligands (H2Yx). MoY1 was crystallized in orthorhombic space group Pbca. The epoxidation of olefins using tert-butyl hydroperoxide and oxidation of sulfides to the sulfoxides by hydrogen peroxide were efficiently enhanced by the catalytic activity of title Mo VI complexes with excellent selectivity. The high efficiency and relative stability of the catalysts was observed by turnover number and UV/Vis investigations. The electron-rich and bulky ligands promoted the effectiveness of the catalysts. Copyright
- Rezaeifard, Abdolreza,Jafarpour, Maasoumeh,Raissi, Heidar,Alipour, Mahboubeh,Stoeckli-Evans, Helen
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experimental part
p. 1023 - 1030
(2012/08/07)
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- Highly selective aqueous heterogeneous oxygenation of hydrocarbons catalyzed by recyclable hydrophobic copper (II) phthalocyanine nanoparticles
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A novel aqueous catalytic method for selective epoxidation of olefins and oxidation of saturated hydrocarbons to ketones using aqueous solution of tetra-n-butylammonium peroxomonosulfate (TBAOX) containing water-insoluble copper (II) phthalocyanine nanoparticles has been developed. No surfactants, additives, toxic reagents or solvents were involved. The impressive turnover numbers obtained for CuPc in this oxidation system displayed the high catalytic activity and relative stability of catalyst. The effective dispersity of CuPc in aqueous solution of TBAOX which yielded particles with average size of 30 nm, was the most important factor to affect the reaction rate. The catalyst could easily be recovered and reused without loss of activity and the reduced form of starting oxidant (n-Bu4NHSO4) could also be recycled.
- Rezaeifard, Abdolreza,Jafarpour, Maasoumeh,Naeimi, Atena,Mohammadi, Khosro
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experimental part
p. 141 - 147
(2012/05/20)
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- Oxidation reactions using polymer-supported 2-benzenesulfonyl-3-(4- nitrophenyl)oxaziridine
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A thermally stable polymer-supported oxidant has been developed. Polymer-supported 2-benzenesulfonyl-3-(4-nitrophenyl)oxaziridine was applied to microwave-assisted reactions that occurred at high temperatures and was shown to oxidize alkenes, silyl enol ethers, and pyridines to the corresponding epoxides and pyridine N-oxides in excellent to good yields and with much shorter reaction times. It also enabled tetrahydrobenzimidazoles to be oxidatively rearranged to spiro fused 5-imidazolones in a more efficient manner. Recycling of the polymer-supported oxidant is also possible with minimal loss of activity after several reoxidations.
- Susanto, Woen,Lam, Yulin
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experimental part
p. 8353 - 8359
(2011/11/12)
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- Benzyltributylammonium periodate as a novel and safe oxygen source for Mn-porphyrin catalyzed practical and highly selective oxygenation of hydrocarbons
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Benzyltributylammonium periodate (BzBu3NIO4) was prepared easily in high yield in neat water. The compound crystallized with two cations and two anions per asymmetric unit and a space group of Pna21 was determined by single-crystal X-ray diffraction. It was used practically in the clean and selective epoxidation of olefins and oxygenation of saturated hydrocarbons catalyzed by manganese (III) porphyrins in water/ethanol as a green media. The catalyst could be reused without noticeable loss of activity, and the oxidant's by-product (BzBu3NIO3) could also be reused. The efficiency of the oxidation system depends critically upon the steric hindrances and electronic structures of both the nitrogen donors and Mn-catalysts. Some evidences suggest the involvement of a high valent Mn-oxo species as well as a six-coordinate [(L)(Por)Mn-OIO3] complex in the oxidation reactions.
- Rezaeifard, Abdolreza,Jafarpour, Maasoumeh,Kavousi, Hossein,Alipour, Mahboubeh,Stoeckli-Evans, Helen
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experimental part
p. 2303 - 2309
(2011/10/09)
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- Synthesis and antibacterial activities of cyclodimers of styrene oxides
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A simple synthetic procedure for preparation of 1,4-dioxanes or 1,3-dioxolanes from styrene oxides is described. Electron-donating groups on the aromatic ring of the styrene oxides were found to favour formation of 1,4-dioxanes while electron-withdrawing
- Mazimba, Ofentse,Majinda, Runner R.,Masesane, Ishmael B.
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experimental part
p. 299 - 304
(2012/05/04)
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- The Ru-catalyzed enantioselective preparation of chiral halohydrins and their application in the synthesis of (R)-clorprenaline and (S)-sotalol
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The asymmetric transfer hydrogenation of a series of halo-substituted aryl methyl ketones, including those substituted in both α-methyl and aryl rings, was studied for the preparation of chiral halohydrins. Up to 99.7% ee was obtained with 2-chloro-1-(2-chlorophenyl)ethanone as the substrate and Ru-CsDPEN as the catalyst in an HCOONa/H2O system. (R)-Clorprenaline, a drug used in the treatment of respiratory disorders, such as bronchitis and asthma, and (S)-sotalol, a class-III antiarrhythmic compound, were prepared with these chiral halohydrins.
- Lu, Chuanjun,Luo, Zonghua,Huang, Ling,Li, Xingshu
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experimental part
p. 722 - 727
(2011/08/06)
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- Iron-catalyzed epoxidation of aromatic olefins and 1,3-dienes
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The combination of iron(III) chloride, pyridine-2,6-dicarboxylic acid and formamidine ligands allows for the epoxidation of styrenes and conjugated dienes in excellent chemoselectivity and yields.
- Schroeder, Kristin,Enthaler, Stephan,Join, Benoit,Junge, Kathrin,Beller, Matthias
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experimental part
p. 1771 - 1778
(2010/09/11)
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- THIAZOLIDINEDIONE ANALOGUES
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The present invention relates to thiazolidinedione analogues that are useful for treating hypertension, diabetes, and inflammatory diseases. In other aspects, the present invention also presents methods of treating hypertension, diabetes, or other inflamm
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Page/Page column 66
(2010/10/03)
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- THIAZOLIDINEDIONE ANALOGUES FOR THE TREATMENT OF HYPERTENSION
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The present invention relates to thiazolidinedione analogues that are useful for treating hypertension, diabetes, and inflammatory diseases. Formula (I), wherein: each of R1 and R4 is independently selected from H, halo, aliphatic, a
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Page/Page column 42
(2009/04/25)
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- Asymmetric dihydroxylation of aryl olefins by sequential enantioselective epoxidation and regioselective hydrolysis with tandem biocatalysts
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Chiral aryl vicinal diols were obtained in high ee and yield by asymmetric dihydroxylation of aryl olefins with tandem biocatalysts: one contains an enantioselective styrene monooxygenase, and the other contains a regioselective epoxide hydrolase.
- Xu, Yi,Jia, Xin,Panke, Sven,Li, Zhi
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supporting information; body text
p. 1481 - 1483
(2009/09/06)
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- An unexpected 1,2-hydride shift in phosphoric acid-promoted cyclodimerization of styrene oxides under solvent-free conditions. A synthetic route towards 2,4-disubstituted 1,3-dioxolanes
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A 1,2-hydride shift in the phosphoric acid-promoted cyclodimerization of styrene oxide and its chloro derivatives under solvent-free conditions leading to 2,4-disubstituted 1,3-dioxolanes is described. Methoxy substituents on the aromatic ring of the styr
- Mazimba, Ofentse,Majinda, Runner R.,Masesane, Ishmael B.
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scheme or table
p. 5927 - 5929
(2010/01/11)
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- Biocatalytic cleavage of alkenes with O2 and Trametes hirsuta G FCC 047
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Alkenes possessing a C=C double bond adjacent to an aromatic ring were cleaved to yield the corresponding carbonyl compounds by use of molecular oxygen as the sole oxidant and a cell-free extract of the wood-degrading fungus Trametes hirsuta FCC 047 as catalyst. The oxygen pressure required was optimized. Special adapted equipment allowed 96 reactions to be performed in parallel under controlled oxygen pressure. A broad spectrum of aryl-alkenes was successfully converted into the corresponding ketones/aldehydes with excellent chemoselectivity under a controlled oxygen atmosphere (2 bar). Wiley-VCH Verlag GmbH & Co. KGaA, 2008.
- Lara, Miguel,Mutti, Francesco G.,Glueck, Silvia M.,Kroutil, Wolfgang
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scheme or table
p. 3668 - 3672
(2009/05/07)
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